Honeywell CM721 Programmable Room Thermostat User Manual
- June 15, 2024
- Honeywell
Table of Contents
Honeywell CM721 Programmable Room Thermostat User Manual
Description
The Honeywell CM721 is a programmable room thermostat designed to control your heating system efficiently, providing comfortable temperatures when you are at home and energy savings when you are away. The following instructions explain how to program and use the thermostat to provide the most home comfort at the least cost.
Controls Layout
- LCD Screen
- Battery Low Indicator`
- Time Display
- Burner On Indicator
- Temperature Display
- Battery Cover
- Program Buttons
- Time Change Buttons
- Set Date Button
- Temperature Change Buttons
- Temperature Enquiry Button
- Operating Mode Buttons
- Green OK Button
- Battery Compartment
Features
- Ergonomic user interface featuring an ‘OK-button’.
- Large LCD (Liquid Crystal Display) Screen.
- 4 independent temperature levels (from 5°C to 35°C).
- Automatic Summer/Winter Time Change.
- Optimum Start to achieve the right temperature at the right time.
- Built-in Memory holds the user program indefinitely.
Getting Started
This section shows you how to setup and run the thermostat in 3 simple steps:
STEP 1: Installing the Batteries
Note: Please follow the instructions in this section only if the
thermostat screen is blank (no symbols or digits are displayed). If the room
temperature is already displayed move on to
Step 2: Setting the Date and Time.
To install the Batteries
- Lift up the front cover of the thermostat to reveal the battery cover and product controls.
- Remove the battery cover by pressing down and sliding out.
- Insert the 2 x AA LR6 Alkaline Batteries supplied with the thermostat, ensuring the correct orientation (see ‘Controls Layout’ on page 2).
- After a short pause the thermostat will display information on the screen and is now ready for use.
- Replace the battery cover by sliding it firmly back into the front of the thermostat.
STEP 2: Setting the Date and Time
To set the Date and Time:
- Press the DATE button to begin setting the date. When you set the date for the first time after the batteries are inserted, the display will show:
- Press the or buttons to set the current day of the month (e.g. d 01 = 1st day of the month) then press the green button to confirm.
- Press the or buttons to set the current month of the year (e.g. m 01 = January) then press the green button to confirm.
- Press the or buttons to set the current year (e.g. yr 06 2006) then press the green button to confirm. The date is now stored.
- Use the or buttons to set the correct time then press the green button to confirm. Each press of the buttons will change the time by one minute and holding them down will change the time slowly at first and get progressively quicker.
Note : If this mode is entered accidentally then press the AUTO, MAN or OFF buttons to exit.
STEP 3: Running the Built-in Heating Program The thermostat is now ready for operation. Press the AUTO button and the built-in heating program will start running. Note: The built-in heating program has been designed to provide normal comfort requirements, but if you want to customise the settings please see the next section ‘Programming the CM721’.
Efficient Daily Use
The Built-in Heating Program
The built-in heating program has 4 temperature level changes that can be set
between 3.00am and 2.50am the following day – allowing you to maintain the
evening temperature after midnight. Each temperature level can be set between
5°C and 35°C, and adjusted in 0.5°C increments. The factory default program
for heating is as follows.
| Period | 1 | 2 | 3 | 4 |
|---|---|---|---|---|
| Time | 6:30 | 8:00 | 18:00 | 22:30 |
| Temperature | 21°C | 18°C | 21°C | 16°C |
Reviewing the Heating Program
To review or edit the heating program use the PROGRAM or buttons to navigate
between the 4 individual programming periods.
Modifying the Heating Program
To change the heating program:
-
Press either of the PROGRAM or buttons to enter the programming mode. The time / temperature settings for period 1 will be flashing as shown.
-
The active period is highlighted by a flashing square around the numbers at the bottom of the screen.
-
To adjust the period start time use the or buttons, the display will stop flashing and the ’ indicator will be displayed. Holding the button down will change the time quickly.
Note : If you are pressing the or buttons and the display flashes the next period, it means the next period will be pushed forward. -
Once the required time is reached press the green button to confirm.
Note: If the original time setting did not require adjustment press the green button to move to step ‘d’. -
The temperature setting for period 1 will now be flashing. To adjust this press the or buttons and confirm the setting again by pressing the green button.
-
The next time and temperature period will now be active. Adjust this by repeating steps b – d above until all 4 periods are set or press the AUTO button to run the program as set, at any time.
Disabling / Enabling Time Periods
The thermostat has 4 periods that can be programmed, but you may not need all
of these switch points for your heating requirements. Therefore, any period
from 2 to 4 can be removed from (or returned to) the heating program profile.
To disable or enable time periods:
- To disable unwanted periods go to the desired period ( 2 to 4 ) using the PROGRAM or buttons to navigate, ensure the correct period is highlighted with the flashing square symbol.
- Press and hold the button for at least 2 seconds and the display will indicate the period has been removed from the program.
- To enable periods again follow the same procedure as above, navigating to the already disabled period. To enable this period again press and hold the button for at least 2 seconds.
Using the Features
Choosing the Operating Mode
- The thermostat can operate in three different modes: Automatic, Manual or Off. To set the operating mode press either of the AUTO, MAN or OFF buttons. The screen indicates which mode is currently active by displaying AUTO, MAN or OFF.
- AUTO (automatic) mode sets the thermostat to follow the built-in temperature program (default or personalised). Operating the thermostat in this mode is the best way to maintain a high level of temperature comfort whilst maximising your energy savings.
- MAN (manual) mode sets the thermostat to act as a simple thermostat with a fixed setpoint throughout the day. The setpoint can be adjusted from 5°C to 35°C by using the or buttons. The thermostat will continue to maintain this temperature until another operating mode or temperature is selected.
- OFF mode sets the thermostat to control to a minimum temperature setting of 5°C (default) that acts as a frost protection measure for your home.
During Normal Operation
Temperature Enquiry In AUTO, MAN and OFF operating modes the thermostat will display the current room temperature. To review the programmed ‘target’ temperature (the temperature which the thermostat is trying to maintain) press the button. This ‘target’ temperature value will be displayed flashing for 5 seconds before returning to the current room temperature value.
Temperature Override
During normal operation (AUTO mode) the programmed temperature can be adjusted
manually by pressing the or buttons or the button. The ‘target’ temperature
will be displayed and flash for 5 seconds – during this time the or buttons
can be used to modify the set value.
Note: This temperature override is cancelled at the next programmed
temperature change.
Adjusting the Time
To adjust only the time during normal operation use the or buttons to adjust
the time and press the green button again to confirm any changes.
Using the Special Features
-
SERVICE indicator
Note: This option only works if activated by your installer. -
The ‘SERVICE’ indicator is displayed at set intervals as a reminder that your heating system requires a routine check. Please call your installer to arrange a maintenance visit.
-
The ‘SERVICE’ indicator will remain on the display of the CM721 until it is either reset or disabled by your installer. The CM721 and heating system will continue to operate as normal.
Automatic Summer/Winter Time Change
The CM721 has a built-in Automatic Summer/Winter Time Change feature that will
automatically adjust the clock forward or backward by one hour for ‘Daylight
Saving Time’. This is carried Bouton the last Sunday of March and October each
year.
Optimum Start
Optimum Start is a program which ensures that the optimum temperature
conditions are achieved at the required times. This is an Energy Efficiency
feature that adjusts the start time of your heating system depending upon how
cold it is. For example, on cold days your heating system will be started
earlier to ensure that your home is warm when you get up (at the target
temperature) and on warmer days the heating system will be started later to
save energy. So, if the Optimum Start Feature is used, then the time /
temperature settings which are entered into the thermostat should be set to
when you want to be warm by and not when you want the heating system to start.
FAQ’s
How do I change the batteries on the thermostat when they run out?
The thermostat constantly monitors the battery power level, which typically
lasts for about 2 years before needing replaced. When the power is running low
a flashing symbol will be displayed on the screen. To change the batteries
follow the steps in the above section.
(‘STEP 1: Installing the Batteries’ on page 3), replacing the used
batteries with new ones in Step c.
Note: While changing the batteries your program settings will be stored
but you may need to adjust the time settings to be correct.
How do I set one temperature for the whole day?
To operate as a simple thermostat with one temperature throughout the day,
select the manual operating mode by pressing the MAN button. Adjust the
temperature by pressing the or buttons – this can be set anywhere from 5°C to
35°C in 0.5°C steps. The thermostat will continue to maintain this temperature
until another operating mode is selected or the temperature is adjusted.
BDR91 Relay Box Controls Layout
The relay box will normally be found mounted close to the boiler.
What does it mean when the BDR91 relay box green LED is ON?
The green LED indicates normal operation of the radio frequency system. When
the green LED is ON the boiler is also ON. When the LED is OFF the boiler is
OFF.
When do I need to use the push button?
You should use the push button to control your boiler only when the RF
communication is lost (see the Troubleshooting Guide).
TROUBLESHOOTING
| Symptom | Remedy |
|---|---|
| Blank Display (Power Loss). | Check batteries are installed by removing the |
battery cover.
Check batteries have been installed in the correct orientation.
Replace the batteries.
Display shows flashing symbol.| The batteries in the thermostat are low on power
– Replace the batteries.
Display shows symbol.| A fault has occurred in your heating system. Remove and re-insert the batteries.
If the symbol does not clear after a few minutes contact your installer.
Display shows the word ‘ SERVICE ‘| Your installer has set a scheduled maintenance alert period on your CM721 as a recommendation that your heating system should receive a routine inspection.
Call your installer to arrange a maintenance visit.
Note: The CM721 and heating system will continue to operate as normal.
BDR91 red LED is constantly on or flashing| RF communication lost due to the wrong location of the room unit – Hook the room unit back on the wall bracket where RF communication was reliable.
**** Call installer
NOTE: You can control the boiler manually when the RF communication is lost: Press the BDR91 push button to switch the boiler on and off. When the green LED is on – the boiler is on.
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